mirror of
https://github.com/denoland/deno.git
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59 lines
1.9 KiB
TypeScript
59 lines
1.9 KiB
TypeScript
// Copyright 2018-2021 the Deno authors. All rights reserved. MIT license.
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// deno-fmt-ignore
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const base64abc = ["A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L",
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"M", "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z", "a",
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"b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p",
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"q", "r", "s", "t", "u", "v", "w", "x", "y", "z", "0", "1", "2", "3", "4",
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"5", "6", "7", "8", "9", "+", "/"];
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/**
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* CREDIT: https://gist.github.com/enepomnyaschih/72c423f727d395eeaa09697058238727
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* Encodes a given Uint8Array, ArrayBuffer or string into RFC4648 base64 representation
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* @param data
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*/
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export function encode(data: ArrayBuffer | string): string {
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const uint8 =
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typeof data === "string"
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? new TextEncoder().encode(data)
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: data instanceof Uint8Array
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? data
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: new Uint8Array(data);
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let result = "",
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i;
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const l = uint8.length;
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for (i = 2; i < l; i += 3) {
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result += base64abc[uint8[i - 2] >> 2];
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result += base64abc[((uint8[i - 2] & 0x03) << 4) | (uint8[i - 1] >> 4)];
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result += base64abc[((uint8[i - 1] & 0x0f) << 2) | (uint8[i] >> 6)];
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result += base64abc[uint8[i] & 0x3f];
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}
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if (i === l + 1) {
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// 1 octet yet to write
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result += base64abc[uint8[i - 2] >> 2];
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result += base64abc[(uint8[i - 2] & 0x03) << 4];
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result += "==";
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}
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if (i === l) {
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// 2 octets yet to write
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result += base64abc[uint8[i - 2] >> 2];
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result += base64abc[((uint8[i - 2] & 0x03) << 4) | (uint8[i - 1] >> 4)];
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result += base64abc[(uint8[i - 1] & 0x0f) << 2];
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result += "=";
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}
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return result;
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}
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/**
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* Decodes a given RFC4648 base64 encoded string
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* @param b64
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*/
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export function decode(b64: string): Uint8Array {
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const binString = atob(b64);
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const size = binString.length;
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const bytes = new Uint8Array(size);
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for (let i = 0; i < size; i++) {
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bytes[i] = binString.charCodeAt(i);
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}
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return bytes;
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}
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